1. Field of the Invention
This invention relates to apparatus for sewing and, in particular, to an apparatus for sewing slide fastener chain to openings of articles.
2. Description of the Prior Art
The prior art, as exemplified by U.S. Pat. Nos. 3,199,479, 3,200,779, 3,329,109, 3,359,931, 3,425,373, 3,442,236, 3,448,705, 3,536,020 3,570,434 and 3,705,446, includes many apparatus for sewing articles including apparatus for sewing slide fastener chain to openings in articles. Some prior art sewing apparatus is highly automated; however such automatic apparatus is usually limited to sewing a single line of stitches in a selected pattern and size on an article. Ribbon-like materials, such as slide fasteners, to be sewed on articles generally vary in length with each different article, making the prior art automatic apparatus impractical for sewing such ribbon-like materials to articles. Other prior art sewing apparatus utilize dual stitching facilities with dual needles to speed sewing of ribbon-like materials to articles; however such dual needle sewing machines generally require manual operations for functions other than forming stitches. Many prior art sewing apparatus employ article guiding facilities but such facilities are generally limited to single ranges of thicknesses of material. Also dual needle sewing machines having a retractable needle, such as Pfaff model No. 122, are available, but the mechanisms for retracting needles are generally complex and/or not adapted for automation; there is generally not available a linear motion apparatus which requires only a small moving force along a linear direction but remains rigid against a force many times as great as the moving force along the linear direction.